Due to its low cost, speed, and freedom from geographical constraints, email has become a ubiquitous and arguably essential means of communication. Unfortunately, the same properties that make it so useful, combined with its openness and trusting design, enable unscrupulous marketers to broadcast email to untargeted audiences. The result is unnecessary and unwarranted costs for recipients.
Recent estimates indicate more than 50% of email is now spam, the volume of spam is growing rapidly, and worldwide costs exceed $20 billion annually. This enormous quantity of unwanted communications has reduced the signal to noise ratio of email to such an extent that it has become an issue of national importance.
Legislative and technological solutions continue to be the primary means pursued to stop or limit spam. No fewer than eight bills are pending before Congress, and more than half the states have enacted laws to regulate email. At the same time, the technology industry is rushing to provide products and services that give individuals and organizations back some control over their mailboxes. In 2002, at least $54.4 million was invested in anti-spam startups, up 65% from the previous year.
Pure technological and regulatory approaches limit unwanted communications by blocking or banning them. This goes against a principle of textbook economics: in terms of individual and aggregate social welfare, a system that facilitates valuable exchange will generally dominate a system that grants universal veto power to either power. An improvement in exchange follows from mechanism design and the principles of information asymmetry. The primary assumption is that the sender composing an email message has a better understanding of its relative value than does the recipient prior to reading it. This private information favors the sender. Therefore, a screening mechanism has been proposed that allows recipients to discriminate between classes of high and low quality senders or conversely a signaling mechanism that allows high quality senders to rise above the noise.
Analogous to a standard bond mechanism, delivering email to an inbox requires an unknown sender to place a small pledge into escrow with a third party. In the case of screening, recipients determine the value of this fee, which they can dynamically adjust to their opportunity costs. After the fee is placed into escrow, the email is delivered. When the recipient opens the email, they may act solely at their discretion to seize the pledge. Taking no action releases the escrow. This mechanism is most appropriate for situations where recipients have no pre-established relationships with the sender. If a recipient expects further communication with a particular sender, they can add the sender to a whitelist which will allow sender messages to pass through the screen unencumbered.
The present invention extends this electronic message system in two respects. First, an innovative method is proposed for managing the whitelist used by electronic message system. Second, an additional method is also proposed for soliciting electronic messages by a solicitor.